Abstract: An ion trap includes a trap exit at which an ion energy adjusting device is located. The adjusting device may be configured for focusing a beam of ions ejected from the trap, reducing the energy distribution of the ions, and/or reducing the average kinetic energy of the ions. The adjusting device may include lenses to which RF and/or DC voltages are applied.

Abstract: Provided is a time-of-flight mass spectrometer having a reflectron which eliminates energy dependency of the flight time of ions having the same m/z while ensuring a high degree of design freedom. An electric field created by the reflectron is virtually divided into a decelerating region for decelerating ions and a reflecting region for reflecting ions. For an ion having a mass-to-charge ratio which has departed with initial energy higher than Ud, the total flight time required for the ion to travel through a free-flight region and the decelerating region into the reflecting region and return will be equal to the total flight time required for an ion of the same mass-to-charge ratio to make a round trip in which the ion turns around at a point of the reference potential value at the boundary between the decelerating region and the reflecting region or in the decelerating region.

Abstract: A High Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) apparatus comprises (a) a first and a second gas inlet; (b) an expansion chamber receiving ions from an ion source and the first and second gas flows from the first and second gas inlets, respectively; (c) an outer electrode having a generally concave inner surface and comprising: (i) an ion inlet operable to receive, from the expansion chamber, the ions and a combined gas flow comprising portions of the first and second gas flows; and (ii) an ion outlet; and (d) an inner electrode having a generally convex outer surface that is disposed in a spaced-apart and facing arrangement relative to the inner surface of the outer electrode for defining an ion separation region therebetween, wherein the combined gas flow and a portion of the ions travel through the ion separation region from the ion inlet to the ion outlet.

Abstract: The present disclosure provides an electron beam column with substantially improved resolution and/or throughput for inspecting manufactured substrates. The electron beam column comprises an electron gun, a scanner, an objective lens, and a detector. In accordance with one embodiment, the electron gun includes a gun lens having a flip-up pole piece configuration. In accordance with another embodiment, the scanner comprises a dual scanner having a pre-scanner and a main scanner, and the detector may be configured between the electron gun and the pre-scanner. In accordance with another embodiment, the electron beam column includes a continuously-variable aperture configured to select a beam current. Other embodiments relate to methods of using an electron beam column for automated inspection of manufactured substrates. In one embodiment, for example, an aperture size is adjusted to achieve a minimum spot size given a selected beam current and a column-condition domain being used.

Abstract: The present invention discloses a method for determining the mineral content represented by the entire SEM-EDS dataset, including initially unknown data points. SEM-EDS data points are taken and compared to a set of known data points. Any data point that is not sufficiently similar to the known data point is classified as unknown and clustered with like unknown data points. After all data points are analyzed, any clusters of unknown data points with a sufficient number of data points are further analyzed to determine their characteristics. All clusters of unknown data points with an insufficient number of data points to allow further analysis are considered outliers and discarded.

Abstract: A method for characterizing identified defects during charged particle beam inspection of a sample is disclosed. The method comprises obtaining a voltage contrast image of the sample by using a charged particle beam imaging apparatus at an inspection temperature; identifying, from the voltage contrast image, the presence of at least one defect on the sample; providing reference data of the sample, wherein the reference data represents at least one reference defect on the sample; comparing the location or geographical distribution of the identified defects and the reference defects on the sample to correlate the identified defects with the inspection temperature thereby characterizing the identified defects.

Abstract: An electron microscope has a focused ion beam column positioned relative to an electron beam column so that the focused ion beam substantially perpendicularly intersects the electron beam. A backscattered electron detector is positioned relative to the focused ion beam column so that the direction normal to a detection plane of the backscattered electron detector is substantially perpendicular to the direction of the focused ion beam. The backscattered electron detector is configured and positioned to detect backscattered electrons released in a spread of at least about 70 degrees in width from the surface of the section by irradiation of the section with the electron beam 1a.

Abstract: An electron microscope is offered which facilitates aberration correction even during high-magnification imaging. The microscope has a spherical aberration corrector, a transfer lens system mounted between the corrector and an objective lens, an aperture stop mounted in a stage preceding the corrector so as to be movable relative to the optical axis, and an angular aperture stop mounted at or near the principal plane of the transfer lens system movably relative to the optical axis to adjust the angular aperture of the electron beam.

Abstract: A system and a method for measuring the thickness of a layer of coating deposited on a substrate indirectly measures the thickness of the layer of coating on the substrate by measuring the thickness of layers of coating on a coating roller before and after the coating is transferred from the coating roller to the substrate. To measure the thickness of the layers of coating on the coating roller two sensors are used directed to respective layer on the coating roller. The sensors have IR radiators and IR detectors.

Abstract: An apparatus and method for a wafer level vacuum package uncooled microbolometer focal plane array (FPA) on a wafer level substrate with a thin film getter-reflector (G-R). The G-R removes gas from the vacuum package and is reflective in the frequency band of the FPA. Sensor pixels are supported about a quarter-wavelength above the G-R which is within the perimeter of the imaging array. The package is evacuated through a single aperture, and vacuum is maintained for the lifetime of the FPA. Imaging sensor size is reduced while maintaining resolution by reducing non-imaging area.

Abstract: An image forming apparatus includes an image forming section that forms an image on a recording material, a human detecting device that detects a person including an optical sensing unit that converts only an upward light of incident light to the optical sensing unit to an electric signal, and a controller unit that controls the image forming section based on the electric signal.

Abstract: A system for surveillance of a delimited area within which people move, wherein at least one hollow optical fiber is configured for extending through the area and is provided throughout its length with a plurality of holes that set an internal channel of the fiber in communication with the outside of the fiber itself. There is provided an optical source configured for supplying the optical signal to one end of the hollow optical fiber and a sensor designed to detect at one end of the hollow optical fiber the optical signal transmitted throughout the length of the fiber itself. A processing unit is configured for examining the spectrum of the optical signal detected by the sensors in order to detect the presence of toxic agents present in the area and drawn into said channel.

Abstract: A covert label structure comprising a three dimensional diffracting optical element layer (100) having a depth profile for producing a predetermined pattern, wherein different portions of a top surface of the diffracting optical element layer (100) have at least two different depths relative to a bottom surface of the diffracting optical element layer (100), wherein the depth profile spans across two dimensions of the top surface of the diffracting optical element layer (100), and wherein the top surface reflects light according to the predefined pattern and an overcoat layer (108) over the top surface of the diffracting optical element layer (100) wherein the overcoat layer (108) is opaque to at least one wavelength of light.

Abstract: An infrared radiation detector includes: a cryostat having a cold finger ensuring heat exchange with a cold source and a window transparent to infrared radiation to be detected; a mechanically fixed cold plane in heat exchange with the cold finger; a detector unit comprising at least a detector circuit sensitive to the infrared wavelength range to be detected, and in direct or indirect heat exchange with the cold plane; and a mechanically fixed cold shield in heat exchange with the cold plane and limiting stray radiation. The cold shield is rotationally symmetrical. An inside wall of the cold shield has a succession of reliefs distributed in at least one helical pattern. A definition axis of the helical pattern coincides with the axis of revolution of the cold shield.

Abstract: A radiological image detection apparatus includes: a phosphor which contains fluorescent material emitting fluorescence in response to radiation exposure; a sensor portion of thin-film type that is provided adjacent to a radiation entering side of the phosphor and supported by the phosphor and that detects fluorescence emitted by the phosphor; and a moisture preventing portion that covers at least a part of a rear face opposite to a phosphor side of the sensor portion so as to suppress entering of moisture into the sensor portion.

Abstract: Provided are sensors and methods for detecting thermal neutrons. Provided is an apparatus having a scintillator for absorbing a neutron, the scintillator having a back side for discharging a scintillation light of a first wavelength in response to the absorbed neutron, an array of wavelength-shifting fibers proximate to the back side of the scintillator for shifting the scintillation light of the first wavelength to light of a second wavelength, the wavelength-shifting fibers being disposed in a two-dimensional pattern and defining a plurality of scattering plane pixels where the wavelength-shifting fibers overlap, a plurality of photomultiplier tubes, in coded optical communication with the wavelength-shifting fibers, for converting the light of the second wavelength to an electronic signal, and a processor for processing the electronic signal to identify one of the plurality of scattering plane pixels as indicative of a position within the scintillator where the neutron was absorbed.

Abstract: Systems and methods are described herein for performing three-dimensional imaging using backscattered photons generated from a positron-electron annihilation. The systems and methods are implemented using the pair of photons created from a positron-electron annihilation. The trajectory and emission time of one of the photons is detected near the annihilation event. Using this collected data, the trajectory of the second photon can be determined. The second photon is used as a probe photon and is directed towards a target for imaging. The interaction of the second probe photon with the target produces back scattered photons that can be detected and used to create a three-dimensional image of the target. The systems and methods described herein are particularly advantageous because they permit imaging with a system from a single side of the target, as opposed to requiring imaging equipment on both sides of the target.

Abstract: A single photon emission computed tomography instrument is provided, which has a platform, at least one detector, at least one beam stopper, a signal processing device and a computer. The at least one detector is disposed at one side of the platform, and the at least one beam stopper is disposed between the platform and the detector. The signal processing device is electrically communicated with the at least one detector, and the computer is electrically communicated with the signal processing device. The present disclosure further provides an operating method which the beam stopper is added or removed respectively while scanning an analyze by the single photon emission computed tomography instrument in different angles. The projection dataset emitted from the focus could be estimated by subtracting the projecting data without the beam stopper from that with the beam stopper, and high resolution image could be obtained by using image reconstruction program.

Abstract: A positron emission tomography method and a device with application adaptability. The method includes: step 1, scanning a tested object for obtaining initial activity information of the tested object; step 2, programming and adjusting a detector module based on the result of the initial scan to obtain a new system structure, and rapidly calibrating the new system structure; step 3, performing a scan with the new system structure for obtaining activity information of the tested object; step 4, analyzing the activity information of the tested object obtained at step 3. If quality of the activity information can satisfy requirements of the application, the scan is finished; otherwise programming and adjusting the detector module is repeated, rapid calibration is performed, and the activity information of the tested object is obtained again with the new system structure until the activity information satisfies requirements.

Abstract: A scintillator detector of high-energy radiation comprising a semiconductor slab that is composed of alternating layers of barrier and well material. The barrier and well material layers are direct bandgap semiconductors. Bandgap of the well material is smaller than the bandgap of the barrier material. The combined thickness of the well layers is substantially less than the total thickness of said slab. The thickness of the barrier layers is substantially larger than the diffusion length of minority carriers. The thickness of the well layers is sufficiently large to absorb most of the incident scintillating radiation generated in the barrier layers in response to an ionization event from interaction with an incident high-energy particle.

Abstract: The present invention provides a radiation measurement device, which shortens periodic interruption periods in the radiation measurements and prevents damage to the amplifier, and a nuclear medicine diagnosis system using such measurement device. The radiation measurement device comprises a semiconductor radiation detector detecting a radiation, a capacitor, which applies voltage to the semiconductor radiation detector, one or more direct current power supplies each capable of making either of positive and negative electric charge collect on one of the electrodes of the capacitor, a constant-current device, which conducts an electric current from the direct current power supplies to the one of the electrodes of the capacitor, and two or more switching devices installed in the wiring connecting the direct current power supplies and the one of the electrodes of the capacitor. Further disclosed is a nuclear medicine diagnosis system equipped with such radiation measurement device.

Abstract: A radiation detector for detecting irradiated radiation that includes: a converting layer for converting radiation irradiated from a radiation source capable of irradiating radiation from two imaging directions, which are different from each other, into electric charges; and a plurality of pixel electrodes for collecting the converted charges. In the radiation detector, when at least one of the two imaging directions forms a specified angle ? with respect to the direction that is orthogonal to the detector plane of the radiation detector, the thickness d of the converting layer and the sizes p of the pixel electrodes satisfy the condition: d·tan ?<k·p (k is a constant of 1 or less).

Abstract: Disclosed is a radiation image capturing device including a control section which detects at least a start of irradiation based on a current value of a current detected by a current detection section, wherein the control section applies an ON-state voltage having a predetermined voltage value from a scan driving section to a switch section via each of scan lines simultaneously so as to perform reset processing of each of radiation detection elements before radiation image capturing, and thereafter, decreases the voltage value of the ON-state voltage simultaneously, monitors the current value outputted from the current detection section while keeping the decreased voltage value of the ON-state voltage, and waits for the start of the irradiation.

Abstract: In a method of count correction for pixels of a pixilated photon counting detector, the average count value output by each of a plurality of pixels during a period of time is determined. A product is determined of the actual average count value and a multiplying correction factor. A corrected count value is then determined for the pixel equal to a sum of the product and an additive correction factor. The multiplying correction factor equals a square root of a quotient of a desired average count value to be output by each of the plurality of pixels during the period of time divided by the actual average count value. The additive correction factor equals a product of the multiplying correction factor and the actual average count value subtracted from the desired average count value.

Abstract: A multi-stream optical interrogation flow cell (60) for a radiopharmaceutical includes a multiple flow cell body (10a-f) defining a first elongate fluid flowpath (A1-6;B1-6) therethrough for individually conducting a radiopharmaceutical therethrough in fluid isolation from other of the flow cell bodies. Each flow cell body further defines a first and second aligned UV transparent optical guides (36,38) and a first interrogation passageway (26a-f) extending between the first and second optical guides such that a portion of the elongate first fluid flowpath intersects the interrogation passageway such that the radiopharmaceutical flows in between the first and second optical guides. The first and second interrogation passageways of all of the flow cell bodies are optically aligned so that a single interrogation beam is able to extend through each of the interrogation passageways.

Abstract: A spherical rotational radiation therapy apparatus (SRRTA) with single spherical rotation center (SRC) is proposed. Referencing a combined X-Y-Z Cartesian and (r-?-?-?) polar coordinates.

Abstract: A hybrid electrostatic lens is used to shape and focus an ion beam. The hybrid electrostatic lens comprises an Einzel lens defined by an elongated tube having a first and second ends and a first electrode disposed at the first end and a second electrode disposed at the second end. The elongated tube is configured to receive a voltage bias to create an electric field within the Einzel lens as the ion beam travels through the hybrid electrostatic lens. The hybrid electrostatic lens further includes a quadrupole lens having a first stage and a second stage, where each of the stages is defined by a plurality of electrodes turned 90° with respect to each other to define a pathway in the Z direction through the elongated tube. The Einzel lens focuses the ion beam and the quadrupole lens shapes the ion beam.

Abstract: The particle beam rotational irradiation apparatus is provided with an irradiation nozzle that irradiates a charged particle beam, a beam transport unit that transports the charged particle beam to the irradiation nozzle, and a rotating unit that can rotate around the isocenter; the particle beam rotational irradiation apparatus is characterized in that the beam transport unit has three or more bending electromagnets and in that the bending electromagnets are arranged in such a way that in the case where as a pair of bending planes, any two of the bending planes of the bending electromagnets are selected, the two bending planes of at least one pair of bending planes are not on the same plane, not parallel with each other, and not perpendicular to each other.

Abstract: This device (2) for generating an ion beam (4) including a liquid metal ion source (18) is characterized in that the ion source is surrounded by a cryogenic trap (28) maintained at a low temperature, this cryogenic trap being able to trap volatile chemical species (G) by condensing them before they can reach the ion source.

Abstract: An apparatus comprises an ionization chamber for providing ions during a process of ion implantation, and an electron beam source device inside the ionization chamber. The electron beam source device comprises a field emission array having a plurality of emitters for generating electrons in vacuum under an electric field.

Abstract: Methods and apparatus for measuring fluorescence, are described. The method includes measuring at least one profile of at least a portion of a surface of a sample, the surface extending substantially transverse an axis, and illuminating the portion of the sample surface with radiation for stimulating fluorescence. The intensity of the radiation varies with position along the axis. Values indicative of the spatial intensity distribution of fluorescence emitted from said portion of the sample surface are measured. The measured values of fluorescence are modified to take account of the spatial variation in intensity of radiation incident upon the surface by utilizing the measured profile.

Abstract: An illumination delivery system for generating sustained secondary emission that includes at least an illumination source, a waveguide, and one or more energy conversion layers is disclosed. Also disclosed are methods of using the inventive illumination delivery system for generating sustained secondary emission.

Abstract: There is provided a system and method for providing and utilizing objects having invisible three-dimensional images. There is provided an object comprising an inner material and an outer material. The inner material is formed in a three-dimensional shape and includes a first portion having a first ratio based on a first fluorescent dye and a first transparent material, wherein the first ratio is selected such as to cause the first portion to remain transparent when exposed to a visible light and the first portion to emit a first visible color when exposed to an invisible light. The outer material comprises a second transparent material formed around the inner material such as to hide the three-dimensional shape of the inner material. By exposing the object to the invisible light, the three-dimensional shape of the inner material is revealed.

Abstract: There are provided with a respiration induction apparatus that induces respiration, based on a desired respiration waveform; a switching device that switches the orbit of a particle beam; and an irradiation apparatus that controls irradiation, in synchronization with the desired respiration waveform. A controller, which performs synchronization control of the switching device and the respiration induction apparatuses in a plurality of treatment rooms, adjusts the periods and the phases of the desired respiration waveforms of the respiration induction apparatuses in the treatment rooms so that the irradiation times synchronized with the desired respiration waveforms in the treatment rooms do not overlap with one another, and controls the switching device so as to switch the orbits of the particle beam, in accordance with the respective irradiation times of the treatment rooms.

Abstract: A method for supplying gas over a substrate in a reaction chamber wherein a substrate is placed on a pedestal, includes: supplying a first gas from a first side of the reaction chamber to a second side of the reaction chamber opposite to the first side; and adding a second gas to the first gas from sides of the reaction chamber other than the first side of the reaction chamber so that the second gas travels from sides of the substrate other than the first side in a downstream direction.

Abstract: A panel for functioning as a barrier to radiation includes at least one layer for restricting the passage of radiation, and the layer for restricting the passage of radiation may be a layer of silicone impregnated with metal, such as tungsten and/or iron. The impregnated silicone layer may be mounted to and supported by at least one other structure of the panel. For example, the impregnated silicone layer may be positioned between, and laminated to, other layers of the panel. In one embodiment, the impregnated silicone layer is positioned between foam layers of the panel to form a core, and the core is positioned between exterior layers of the panel. One or more exterior layers of the panel may be in the form of sheet metal or any other suitable structure.

Abstract: Boron cage compound-containing materials for shielding and absorbing neutrons. The materials include BCC-containing composites and compounds. BCC-containing compounds comprise a host polymer and a BCC attached thereto. BCC-containing composites comprise a mixture of a polymer matrix and a BCC filler. The BCC-containing materials can be used to form numerous articles of manufacture for shielding and absorbing neutrons.

Abstract: A thermal neutron shield comprising boron shielding panels with a high percentage of the element Boron. The panel is least 46% Boron by weight which maximizes the effectiveness of the shielding against thermal neutrons. The accompanying method discloses the manufacture of boron shielding panels which includes enriching the pre-cursor mixture with varying grit sizes of Boron Carbide.

Abstract: According to one embodiment, a nonvolatile memory device includes a word line interconnect layer, a bit line interconnect layer, a pillar, and charge bearing members. The word line interconnect layer includes a plurality of word lines extending in a first direction. The bit line interconnect layer includes a plurality of bit lines extending in a second direction that intersects the first direction. The pillar is disposed between each of the word lines and each of the bit lines. The charge bearing members contain a negative fixed charge, and provided on side faces of the pillars. The pillars includes a diode film provided with a p-type layer and an n-type layer and a variable resistance film stacked on the diode film. The charge bearing member is disposed on side faces of the p-type layer, and is not disposed on side faces of the n-type layer.

Abstract: According to one embodiment, a memory device includes a first electrode, a second electrode, and a variable resistance film. The variable resistance film is connected between the first electrode and the second electrode. The first electrode includes a metal contained in a matrix made of a conductive material. A cohesive energy of the metal is lower than a cohesive energy of the conductive material. A concentration of the metal at a central portion of the first electrode in a width direction thereof is higher than concentrations of the metal in two end portions of the first electrode in the width direction.

Abstract: A non-volatile memory device may include a first wordline on a substrate, an insulating layer on the first wordline, and a second wordline on the insulating layer so that the insulating layer is between the first and second wordlines. A bit pillar may extend adjacent the first wordline, the insulating layer, and the second wordline in a direction perpendicular with respect to a surface of the substrate, and the bit pillar may be electrically conductive. In addition, a first memory cell may include a first resistance changeable element electrically coupled between the first wordline and the bit pillar, and a second memory cell may include a second resistance changeable element electrically coupled between the second wordline and the bit pillar. Related methods and systems are also discussed.

Abstract: A resistive memory device may include a substrate, gate electrode structures, a first impurity region, a second impurity region, a first metal silicide pattern and a second metal silicide pattern. The substrate may have a first region where isolation patterns and first active patterns may be alternately arranged in a first direction, and a second region where linear second active patterns may be extended in the first direction. The gate electrode structures may be arranged between the first region and the second region of the substrate. The first and second impurity regions may be formed in the first and second impurity regions. The first metal silicide pattern may have an isolated shape configured to make contact with an upper surface of the first impurity region. The second metal silicide pattern may make contact with an upper surface of the second impurity region.

Abstract: An exemplary embodiment of the present invention discloses an LED chip including a substrate, a GaN-based compound semiconductor stacked structure arranged on the substrate, an electrode electrically connected to the semiconductor stacked structure, and a wavelength converting layer covering a portion of the semiconductor stacked structure. The electrode passes through the wavelength converting layer. The semiconductor stacked structure includes a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer.

Abstract: A nanostructured device according to the invention comprises a first group of nanowires protruding from a substrate where each nanowire of the first group of nanowires comprises at least one pn- or p-i-n-junction. A first contact, at least partially encloses and is electrically connected to a first side of the pn- or p-i-n-junction of each nanowire in the first group of nanowires. A second contacting means comprises a second group of nanowires that protrudes from the substrate, and is arranged to provide an electrical connection to a second side of the pn- or p-i-n-junction.

Abstract: Disclosed herein is a quantum dot phosphor for light emitting diodes, which includes quantum dots and a solid substrate on which the quantum dots are supported. Also, a method of preparing the quantum dot phosphor is provided. Since the quantum dot phosphor of the current invention is composed of the quantum dots supported on the solid substrate, the quantum dots do not aggregate when dispensing a paste obtained by mixing the quantum dots with a paste resin for use in packaging of a light emitting diode. Thereby, a light emitting diode able to maintain excellent light emitting efficiency can be manufactured.

Abstract: Disclosed herein are gallium nitride based light emitting diodes having interlayers with high dislocation density and a method of fabricating the same. The light emitting diode includes: a substrate; a buffer layer disposed on the substrate; an n-type contact layer disposed on the buffer; a p-type contact layer disposed on the n-type contact layer; an active layer interposed between the n-type contact layer and the p-type contact layer; a first lower semiconductor layer interposed between the buffer layer and the n-type contact layer; and a first interlayer interposed between the first lower semiconductor layer and the n-type contact layer, wherein the first interlayer has lower dislocation density than the buffer layer and higher dislocation density than the first lower semiconductor layer. This way, the interlayers with higher dislocation density prevent dislocations formed within the first lower semiconductor layer from being transferred to the n-type contact layer.

Abstract: A display apparatus includes a first substrate including a plurality of pixels, a first electrode arranged on the first substrate, a second substrate facing the first substrate, and a second electrode arranged on the second substrate and spaced apart from the first electrode, the second electrode to form an electric field in cooperation with the first electrode. At least one of the first and second electrodes includes a transparent conductive nanomaterial having a transmittance of no less than 73% to no more than 100% and a sheet resistance of 0 ohms to 100 ohms.

Abstract: A memory device can include an active layer that has a selectable lateral conductivity. The layer can include a plurality of nanoparticles.

Abstract: Disclosed herein is a nano device, including: a carbon layer including one-layered graphene having a honeycombed planar structure in which carbon atoms are connected with each other and two or more-layered monocrystalline graphite; and one or more vertically-grown nanostructures formed on the carbon layer. This nano device can be used to manufacture an integrated circuit in which various devices including a graphene electronic device and a photonic device are connected with each other, and is a high-purity and high-quality nano device having a small amount of impurities because a metal catalyst is not used.

Abstract: A graphite-based device comprising a substrate with a plurality of zones and one or more graphene stacks overlaying the zones is provided. A first zone comprises a plurality of surfaces. A first surface is adjacent to a second surface in the plurality of surfaces. The one or more graphene stacks comprise a first graphene stack in the first zone. The first graphene stack comprises a plurality of graphene layers, a first of which is formed on the first surface. The first graphene layer is either planar or non-planar. A second graphene layer in the plurality of graphene layers comprises a first portion formed on a top surface of the first graphene layer, a second portion formed on the second surface and a first intermediate portion connecting the first and second portions. The second graphene layer is non-planar. The first and second graphene layers have different characteristic dimensions and different bandgaps.